Pipette dispenser



y 1960 R. o. TAYLOR ETAL 2,93

PIPETTE DISPENSER Filed Jui :51, 1956 2 Sheets-Sheet 1 &

Q Q g INVENTORS RICHARD 0. TAYLOR EDWARD s. KLINE 74 R. O. TAYLOR ET ALP'IPETTE DISPENSER 2 Sheets-Sheet 2 Filed July 31, 1956 INVENTORSRICHARD O. TAYLOR EDWARD S. KL/NE BY A77'0fi/VE/S United States Patent OPIPETTE DISPENSER Richard 0. Taylor, Greenbelt, Md., and Edward S.Kline, Falls Church, Va., assignors to the United States of America asrepresented by the Secretary of the Army Filed July 31, 1956, Ser. No.601,329

3 Claims. (Cl. 221-248) (Granted under Title 35, US. Code (1952),sec.'266) The invention described herein may be manufactured and used byor for the Government for governmental purposes without the payment ofany royalty thereon.

It being frequently essential for pipettes to be sterile for use, andsubstantial numbers being required often, it is standard procedure forsterilizing such instruments to wrap them in a special paper and placethem on a rack within an autoclave. To maintain the pipettes in thesterile condition, they would have to be kept within the autoclave orwithin the paper until ready for use. Each time a single pipette wasneeded either the autoclave would be opened and the single pipettewithdrawn, or else the paper would have to be unwrapped. The opening ofthe autoclave was inconvenient and exposed other instruments left in itto contamination by air. In addition, opening the autoclave required theuse of both hands, which itself is inconvenient and time consuming insome laboratory procedures. Unwrapping the paper covering also involveduse of both hands, and more importantly, incurred likelihood of loss ofsterility.

From the foregoing, it may be said to be an object of the presentinvention to provide apparatus which dispenses an individual pipetteunder sterile conditions.

Another object of this invention is to provide a dispenser of pipetteswhich is convenient to operate.

A further object of this invention is to provide apparatus which willdeliver individual pipettes in a sterile condition after storage. v

A still further object of this invention is to provide a dispenser ofpipettes that may be operated by one hand.

. Another object of this invention is to provide a pipette dispenser inwhich a number of pipettes may be sterilized simultaneously.

A still further object of this invention is to provide apparatus whichwill store and maintain pipettes in a sterile condition.

Other objects of this invention will appear as the description proceeds,and the features of novelty will be pointed out in particularity in theappended claims.

In the drawings:

Fig. l is a perspective view of the complete pipette dispenser with thecover closed;

Fig. 2 is a side view of the pipette dispenser showing in outline apipette ready for delivery and with the closure door outlined in itsopen position;

Fig. 3 is an end view of the discharge end of the dispenser illustratingthe pipette closure door, this end being labeled a in Fig. 2;

Fig. 4 is an end view of the opposite, or plunger end of the dispenser,this end being labeled b in Fig. 2;

Fig. 5 is a transverse vertical sectional view ofv the dispenser, theview being taken along the line 5 5 of Fig. 2 looking in the directionof the arrows;

Fig. 6 is a fragmentary sectional view of the lower left hand end of thedispenser illustrated in Fig. 2, the view being indicated by the line6-6 of Fig. 3;

Fig. 7 is a vertical sectional longitudinal view ofthe dispenser, theview being taken generally along the longitudinal center line as shownby the line 7--7 of Fig. 3;.and

Fig. 8 is a top fragmentary sectional view of the right hand end of thedispenser as viewed in Fig. 7, the view being along the line 88 of Fig.7, looking in the direction of the arrows.

In Fig. 1 the entire pipette dispenser is shown with cover 1 closing thebody of a hopper-like dispenser receptacle formed by side walls 4 and 4and the front wall 3 and back wall 5. Cover 1, as well as all otherparts, is preferably composed of a non-corrosive metal such as aluminum.Cover 1, shown with reinforcing integral peripheral flange 2,frictionally fits snugly over the receptacle, yet is not air-tight.Preferably, cover 1 comes down over the top of the hopper for asubstantial distance, for example, one inch. The design of the cover isa studied result of the use of the dispenser. For sterilization, thedispenser is placed in an autoclave, and for this purpose cover 1 cannotbe steam-tight. After removal from the autoclave, the dispenser may bestored in the open air. The cover should be reasonably tightfitting andprovide an ascending air passage only, so that dust and germs will notenter the dispenser and contaminate the sterile pipettes.

Front 3 and back 5 walls extend equally below the sidewalls of thehopper and are bent at their bottoms to provide flanged support for thedispenser as shown at 3 and 5. Other supporting means may also beutilized. The side walls 4 and 4, which for convenience may be made ofone continuous metal sheet, have substantially straight and parallelupper portions for receiving the cover 1, 1

from which upper portions the side walls of the hopper converge inwardlyequally and downwardly to a radial junction having a curvature and widthapproximately corresponding to similar values of the pipettes beingdispensed so that one at a time of such pipettes is received at thisjuncture.

To perform the two operating functions of the dispensing apparatus,plunger 11 is moved inwardly toward the end wall 3. Simultaneously, thedispenser door 18 is opened by engagement therewith of long plunger rod8,

. then the pipette which is in the juncture between the side walls ispushed partially through the opened door by movement of the shortplunger rod 16 against the pipette, so that the end of the pipette doesnot contact against the door 18 prior to opening thereof, therebyavoiding any likelihood of breaking the pipette. Thus, an individualsterile pipette is ejected. Plunger 11 is the connecting bridge betweenthe two rods 8 and 16 which perform the opening of the door closure andthe pipette ejectment, respectively. Rods 8 and 16 both pass through rodguide 10 which, by means of flange 12 and screws 15, is connected tofront wall 3. Rod 8, which opens the closure door, is positioned in achannel in rod guide 10, through an aperture in front wall 3, along sideof and substantially parallel to the slanting side wall 4', throughguide 6, and finally through an aperture in back wall 5, so as to strikeagainst door 18 when plunger 11 is moved toward front wall 3. In orderto return plunger 11 and its connected rods 8 and 16 to their normalpositions, a circular spring 13 is positioned around rod 8 in thatportion of rod 8 between plunger 11 and rod guide 10. Rod 8 is limitedin its movement by stop 20 secured thereto.

The nearly simultaneous ejectment of the pipette and opening of thedispenser closure door may be seen more clearly by reference to Fig. 2,a side view of the dispenser. The closure opening rod 8 is positioned soas to apply pressure onto door 18 a moment previous to the ejectment ofthe pipettes through the dispenser side orifice 24. This arrangement-.is dictated by the object of having rod 8 apply the opening pressureonto door 18 and avoiding pipette 23 applying such pressure. If the dooropening pressure were supplied by pipette 23, the pipette might break orbecome contaminated.

An imortant feature of this invention is the maintenance of door 18 inits open position after partial ejectment of pipette 23 and untilpipette 23 is fully removed from out of the dispenser. This featureenables numerous pipettes to be individually removed from the dispenser,an operator having to use only one hand. In this operation, plunger 11is moved toward front wall 3, compressing spring 13. Rods 8 and 16simultaneously slide in the direction from front wall 3 to back wall 5.Rod 8 pushes against door 18 raising the door from its closed positionover orifice 24 and flat against back wall to its open position at someangle approaching the perpendicular to wall 5. Simultaneously, rod 16pushes against the end of pipette 23 thereby moving the pipetteoutwardly through orifice 24. When plunger 11 is pushed all the way inuntil stop 20 contacts wall 5, the pipette 23 will protrude aboutone-half to one inch beyond back wall 5. This protruded length willsupport closure 18 and maintain it in its open position until thepipette is completely removed from the hopper, which is done by graspingthe projecting end of the pipette with one hand or a suitableinstrument, and pulling the pipette completely from the hopper,whereupon the weight 19 closes the door 18 without exposure of theremaining pipettes in the hopper to contamination from the surroundingair. Plunger 11 is next released, whereupon spring 13 causes plunger 11and rods 8, 16 to move to return to their original positions.

The closure mechanism may be seen more clearly by reference to Fig. 3.The closure door 18 is hinged with door mount 25 on pin pivot 22.Closure mount 25 is soldered to end wall 5. The diameter of orifice 24is determined by the size of pipettes utilized, as well as the width ofthe radial junction between the side walls. Of course, for a dispenserof various sized pipettes orifice 24 should be larger than the diameterof the largest pipettes used.

Fig. 4 is a view of front wall 3 showing plunger 11 and atfixed theretorods 8 and 16. These rods pass through rod channels 16 and 10' in rodguide 10. Rod guide 10 is fastened to end wall 3 by means of screws 15through flange 12 on this rod guide.

Fig. 5 illustrates the convergence of side walls 4 and 4. Thisconvergence allows only one pipette at a time to be within the radialjunction between the convergent side walls and between the internal endof rod 16 and orifice 24. In order to insure that pipette 23, whenpushed by rod 16, will slide along in the said radial junction betweenthe side walls 4 and 4 and through orifice 24, guide 26 is provided.This internal strip guide 26 prevents more than one pipette from fallinginto the radial junction and also prevents the pipette which is in theradial junction from rising out of it under pressure from rod 16.

Fig. 6 illustrates clearly the opening of closure 18 by rod 8. Pipette23, which is shown starting to protrude from the dispenser throughorifice 24, does not push against closure 18 in the opening of thisclosure.

Fig. 7 is a side cut-away view of the entire dispenser. The straightalignment along a substantially common horizontal axis of rod 16,pipette 23, and orifice 24 may be clearly seen.

In practice, the dispenser of the present invention has proven itsactual utility in many bacteriological tests.

For example, the dispenser was filled with 5 ml. serological pipettesand sterilized in an autoclave with wet heat for one hour at 15 lbs. persquare inch of steam pressure. The dispenser was allowed to cool andstand in an open laboratory room for four days. Ten pipettes wereremoved, at random times, from the dispenser during the four day period.After the four days another pipette was removed, swabbed thoroughly, theswab placed in media and incubated. No contamination was observed. Thisprocedure was repeated during a period of two weeks for pipettes withsterility checks made on several pipettes and closure door 18. None ofthese sterility tests showed any trace of contamination.

Having thus described our invention, what we claim as new and wish tosecure by Letters Patent is:

1. An apparatus for dispensing sterile pipettes while maintaining thesame, as well as pipettes remaining in the apparatus, in sterilecondition until dispensed, which comprises, in combination, a hopper forcontaining the pipettes, the hopper having a body defined bysubstantially equally and downwardly converging opposite side wallswhich are downwardly convergent to a radial junction having a curvatureand width approximately corresponding to similar values of pipettes tobe dispensed, whereby the pipettes sequentially drop into the juncturefor sequential dispensation therefrom, the hopper having opposite endsclosed by a pair of opposite closure end walls therefor, one of the endwalls having a dispensing opening therein registering with the radialjunction between the side walls through which opening the pipettes inthe hopper may be sequentially ejected, a closure door for the openinghingedly mounted exteriorly on the end wall adjacent to the dispensingopening and being vertically hinged movable with respect to the end wallduring its opening and closing movements, a counterweight on the doornormally maintaining the door in closing position, the other of the pairof end walls being a plungermounting wall and having spaced openingstherethrough for reception of a pair of spaced parallel plunger rodsincluded in plunger means mounted on the outside of the said end walland extending therethrough, the pair of plunger rods being ofsubstantially unequal length, the longer rod being positioned outsidethe hopper at a level higher than said dispensing opening and having alength greater than that of the hopper when the plunger means are movedinwardly towards the plunger-mounting end wall, the longer rod bearingagainst the closure door for the dispensing opening in the opposite endwall for pushing the door open, the shorter plunger rod engaging apipette in the radial junction between the side walls and partiallyejecting the pipette through the opened door responsively to continuedinward movement of the plunger relative to the plunger end wall, guidemeans for the plunger rods mounted exteriorly on the plunger end wall, aconnecting yoke rigidly interconnecting the plunger rods forsimultaneous parallel movement thereof, and a coil spring enclosingportions of a plunger rod compressed between the guide means and theyoke for normally urging the yoke and plunger rods to outward positionwith respect to the plunger end wall upon release of operating pressureon the plunger and removal of a partially ejected pipette through theopen dispensing door, the counterweight for the door returning the doorto closed position responsively to complete removal of the ejectedpipette from the door, such removal enabling a following pipette toenter the juncture between the side walls of the hopper.

2. The dispensing apparatus of claim 1, wherein the convergent sidewalls of the hopper are surmounted by upright parallel upper portions,and a cover frictionally enclosing substantial upper portions of theside walls and of the end walls and defining therewith steam passagesfor escaping steam produced during sterilizing operations, whileinhibiting ingress into the apparatus of contaminating air subsequent tosuch sterilizing operations.

References Cited in the file of this patent UNITED STATES PATENTS 67,317Killin et a1 July 30, 1867 602,593 Axelson et a1. Apr. 19, 1898 846,314Kabele Mar. 5, 1907 939,657 Beatty Nov. 9, 1909 6 Axelson et al. Apr. 5,1932 Tilletson Oct. 24, 1933 Lloyd Feb. 6, 1934 ODonnell Mar. 16, 1937Petrecca Dec. 8, 1953 FOREIGN PATENTS Sweden Mar. 7, 1908 Germany Feb.25, 1939 Italy Oct. 1, 1935 Italy Mar. 29, 1949 Germany May 16, 1928

